<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>v-model</title>
    <script src="https://unpkg.com/vue"></script>
</head>
<body>
<div id="app">
    <h1>{{msg}}</h1>
    <input type="text" name="" id="" v-model:value="msg" style="width:200px;">
</div>

</body>
<script>
    var vm = new Vue({
        el: '#app',
        data: {
            msg: '大家好哈哈哈哈，你们好啊。'
        },
        methods: {

        }

    })
</script>
</html>